I have been hit and cut by a 15" square piece of flying MDF, kicked back when it bound between fence and blade. Just missed my face. Important issue.
– bibMar 17 '15 at 16:26

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In my middle school shop class, someone was ripping a piece of 2x4. The kickback shot it about 35' across the classroom area of the shop (where all the desks were) and left a huge dent in the chalkboard right behind the teacher's desk. Definitely an important issue!
– FreeManMar 17 '15 at 20:23

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If you want a bragging contest about how bad of a kickback you witnessed please take it to chat.
– ratchet freakMar 17 '15 at 20:25

6 Answers
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Having a fence parallel to the blade. When it's not parallel, you might pinch the blade and cause the workpiece to fly back at you.

Don't rip boards in half. If you have a six inch board that you cut in half, you're relieving a lot of tension in the wood and may get significant wood movement while cutting. Again, you might pinch the blade and get dangerous kickback. It's always better to rough cut on the bandsaw first.

Edit: One other thing to consider--I generally use two pushsticks like Mattias Wandel (https://www.youtube.com/watch?v=gdIQY_7T26k) so that keeps me on the side of the piece rather than behind it. That way, if kickback does happen, I'm out of harm's way.

Edit #2: I had to come back and add one more thing tangentially related to the OP. I read an article about someone using a sawstop who turned off the safety feature and lost his thumb. It looks like he was thinking about kickback (and using two pushsticks) and reached across the blade to free his workpiece. Bad idea.

Came here to say riving knife. I have experienced kickback while using one, but it was my own stupidity. I hadn't bothered to raise the riving knife back up after performing a non-through cut. Luckily it was with a small square of plywood I was cutting, and it didn't have enough mass to do much damage when it hit me. I've never made that mistake again, and never experienced kickback again.
– DoresoomMar 17 '15 at 15:48

It only takes one time! I was cutting a drawer to fit without a riving knife. I tell you, a drawer has a LOT of mass! I slammed into my stomach and knocked the wind out of me.
– dfifeMar 17 '15 at 15:51

Your first auxiliary point is important to consider, as most saws have adjustments to keep the fence and the blade in proper alignment. Good point!
– datUserMar 17 '15 at 18:23

Most kick back I've seen has to do with things getting trapped on an angle. I see some featherboards mentioned later.
– NipFuFeb 24 '16 at 7:13

Kickback can occur when the back of the blade gets pinched in the kerf, when a piece of wood is pinched between the blade and fence, or when a piece of wood is lifted off the table.

Anti-kickback equipment

As others have mentioned, a riving knife, anti-kickback pawls, and fence-mounted featherboards help protect against kickback.

If using a table-mounted featherboard, make sure it is positioned before the blade (infeed side). If you position the featherboard alongside the blade or after the blade, the featherboard will actually cause your wood to pinch the blade and cause kickback.

Other types of equipment include fence-mounted rollers and manual or automatic feeders.

Fence-mounted rollers are similar in function to fence-mounted featherboards but also help push the stock against the fence. The rollers are typically designed to only rotate in one direction.

Manual feeder:

Power Feeder:

A splitter is not as good as a riving knife

If you have an older saw, you may have a splitter instead of a riving knife. Although a splitter and riving knife both prevent the blade from being pinched, a splitter is always positioned at the same height, while a riving knife raises and lowers with the blade. This allows the riving knife to maintain a constant distance from the back of the blade. This means that when the blade is lowered for a shallow cut, there is a huge gap between the back of the blade and the splitter, as illustrated in a kickback incident analyzed on LumberJocks. A splitter only performs as well as a riving knife when the blade is raised to full height--which itself is considered unsafe unless you need the full height of the blade to make a cut.

Crosscuts

There are some additional safety measures you can employ when making crosscuts.

Use a sled for crosscutting. The sled cradles your workpiece all the way through the blade and pushes both pieces past the blade after the cut.

Don't use your miter gauge and fence together. If you want to use the fence as a stop to cut off consistent lengths, clamp a piece of wood to the fence before the blade (on the infeed side). This way, the cutoff cannot be trapped between the blade and fence.

Think through the entire cut before you make it

Before you make any cut with any power tool, you should carefully think through the entire cut, from start to finish. Some of the concerns mentioned below can directly contribute to (or prevent) kickback, but all of them are important.

How will you push the entire length of the workpiece into, through, and past the blade?

Is there anything that could potentially block the path of the workpiece?

Where will each hand be through the entire operation?

What will happen to the offcut?

Will you be cutting through any knots or other unstable features?

What will happen when the workpiece is past the blade? Will it teeter on the back end of the saw (and possibly fall off)?

Do you need infeed or outfeed supports?

Where is the power switch, and how will you turn off the saw if the workpiece gets stuck and you cannot push it all the way through the blade? Can you turn it off with your knee so you don't have to move your hands?

Stand clear

Although it doesn't necessarily do anything to prevent kickback, you should always try to stand clear of the likely path of a kickback. In particular, stand off to the side of your workpiece if possible, and if you're using the fence do not stand in the zone between the blade and the fence.

Is a fence mounted roller (like the yellow ones in photo) available to buy? If so, where might I find one? thanks, R
– user713Jun 5 '15 at 21:11

@Randy The yellow ones pictured are called Board Buddies, and the black ones are sold as the JessEm Clear Cut TS. You can find these and maybe a few others by searching for "table saw roller guide" or "table saw stock guide." Most woodworking tool stores sell them.
– rob♦Jun 5 '15 at 21:28

The photo shows a router table rather than a table saw, but you are correct that a fence-mounted featherboard can help against kickback. If you use a table-mounted featherboard and you're making a through cut, be sure to position the featherboard before the blade (the infeed side).
– rob♦Mar 17 '15 at 18:06

@rob yes I know it's a router, if I have time I'll find one with a table saw
– bowlturner♦Mar 17 '15 at 18:07

Featherboards against fence (before the blade) and downward against the table can deff help on those hairy cutting operations.
– datUserMar 17 '15 at 18:17

Keep the larger piece between the blade and fence, and push on that with your push-stick. Most kick-backs I've seen were when a narrow piece was pinched between the blade and fence. And don't stand behind the piece!

Be extra careful twisted or knotted lumber that may have alot of internal tension - much more likely to pinch & kick back.

Aftermarket riving knives tend to range from unavailable to sub-optimal.

The function of the riving knife is to keep the wood from catching on the rising teeth of the blade. This can happen either through operator error, or from the wood springing to a new shape with the creation of the kerf.

Splitters do this too, but are usually further from the blade, and cannot be used with tilted blades.

I had an old rockwell-beaver with no guard, no splitter, no riving knife. I still have all my fingers. Large collection of push sticks, and about two pounds of paranoia, and NEVER stand in the plane of the blade.

Anyway:

If your fence is set up with a track for jigs, you can get wheels that are slightly out of line, and are spring loaded. They ride up on the board, and will pull the board toward the fence. This reduces the chance of the kerf catching on the rising blade.

This one from Jessem, is more solid looking.

Couple this with a feather board. The most common style locks into a miter guage slot. There are some slick ones now that have releaseable magnet hold downs, and can both push in and down. This ensures that the board is tight to the fence at the start of the cut. Featherboards can also be mounted on the fence to push down

You can also get pawls that attach the the fence. This only engages if you have kickback, and does little to prevent it from happening in the first place.